[Genetic causes of male infertility]

In this review, after a brief summary of the spermatogenesis process, we present some genetic causes of male infertility at chromosome and gene level, known at present. Even though knowledge has greatly increased, in 15% of cases, we still do not know the infertility mechanism. The genotype-phenotype relationship remain ambiguous because of the diversity of the implicated mechanisms and their interactions. Other genes remain to be identified and, in the future, one of the main difficulties will be to define exactly the relationship between environmental factors and male infertility.